The present project is proposed to continue work toward establishing the effects of treatment for sentence deficits in agrammatic (Broca's) aphasia. In this research we examine the relevance of linguistic theory to understanding sentence breakdown and recovery patterns in aphasia and gather data to further developing accounts of normal sentence production. We plan to build on previous work highlighting the important role that linguistic structure can play in guiding treatment for aphasia. In particular, we examine and manipulate lexical and syntactic properties of sentences that are the most difficult for agrammatic aphasic subjects. We focus on (a) sentence structures (e.g., filler gap structures) in which noun phrases (NPs), and other elements (e.g., verbs and auxiliaries) have been moved out of their original d-structure positions, (b) functional categories (e.g., verb tense morphology and complementizers), and (c) verb and verb argument structure. We also continue to test the hypothesis that training more complex rather than simple structures will result in greater improvement in aspects of sentence production and comprehension. We define sentence complexity in terms of the (a) type of movement involved in sentences, i.e., wh- and NP-movement, (b) phrasal tree structure and the relation between nodes in the syntactic tree, and (c) the number and type of embeddings. In addition, we consider the lexical properties of verbs and how they impact syntactic operations in determining complexity. In this period we also extend our work to begin to understand mechanisms that generate observed recovery patterns. Using head-mounted eyetracking, we examine filler gap processing in normal participants and in aphasic patients prior to and following treatment. FMRI studies also are included to examine the neural mechanisms of recovery. While neuroimaging studies have begun to elucidate the neural correlates of language, few have examined brain sites recruited by aphasic patients, and even fewer have studied the neural mechanisms supporting recovery. FMRI studies undertaken in the previous cycle showed important changes in activation patterns from pre- to post-treatment. We, therefore, continue this effort in our continuing studies.